001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache license, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the license for the specific language governing permissions and 015 * limitations under the license. 016 */ 017package org.apache.logging.log4j.core.appender; 018 019import java.io.IOException; 020import java.io.OutputStream; 021 022import org.apache.logging.log4j.core.Layout; 023 024/** 025 * Manages an OutputStream so that it can be shared by multiple Appenders and will 026 * allow appenders to reconfigure without requiring a new stream. 027 */ 028public class OutputStreamManager extends AbstractManager { 029 030 private volatile OutputStream os; 031 protected final Layout<?> layout; 032 033 protected OutputStreamManager(final OutputStream os, final String streamName, final Layout<?> layout) { 034 super(streamName); 035 this.os = os; 036 this.layout = layout; 037 if (layout != null) { 038 final byte[] header = layout.getHeader(); 039 if (header != null) { 040 try { 041 this.os.write(header, 0, header.length); 042 } catch (final IOException ioe) { 043 LOGGER.error("Unable to write header", ioe); 044 } 045 } 046 } 047 } 048 049 /** 050 * Creates a Manager. 051 * 052 * @param name The name of the stream to manage. 053 * @param data The data to pass to the Manager. 054 * @param factory The factory to use to create the Manager. 055 * @param <T> The type of the OutputStreamManager. 056 * @return An OutputStreamManager. 057 */ 058 public static <T> OutputStreamManager getManager(final String name, final T data, 059 final ManagerFactory<? extends OutputStreamManager, T> factory) { 060 return AbstractManager.getManager(name, factory, data); 061 } 062 063 /** 064 * Default hook to write footer during close. 065 */ 066 @Override 067 public void releaseSub() { 068 writeFooter(); 069 close(); 070 } 071 072 /** 073 * Writes the footer. 074 */ 075 protected void writeFooter() { 076 if (layout == null) { 077 return; 078 } 079 final byte[] footer = layout.getFooter(); 080 if (footer != null) { 081 write(footer); 082 } 083 } 084 085 /** 086 * Returns the status of the stream. 087 * @return true if the stream is open, false if it is not. 088 */ 089 public boolean isOpen() { 090 return getCount() > 0; 091 } 092 093 protected OutputStream getOutputStream() { 094 return os; 095 } 096 097 protected void setOutputStream(final OutputStream os) { 098 final byte[] header = layout.getHeader(); 099 if (header != null) { 100 try { 101 os.write(header, 0, header.length); 102 this.os = os; // only update field if os.write() succeeded 103 } catch (final IOException ioe) { 104 LOGGER.error("Unable to write header", ioe); 105 } 106 } else { 107 this.os = os; 108 } 109 } 110 111 /** 112 * Some output streams synchronize writes while others do not. Synchronizing here insures that 113 * log events won't be intertwined. 114 * @param bytes The serialized Log event. 115 * @param offset The offset into the byte array. 116 * @param length The number of bytes to write. 117 * @throws AppenderLoggingException if an error occurs. 118 */ 119 protected synchronized void write(final byte[] bytes, final int offset, final int length) { 120 //System.out.println("write " + count); 121 try { 122 os.write(bytes, offset, length); 123 } catch (final IOException ex) { 124 final String msg = "Error writing to stream " + getName(); 125 throw new AppenderLoggingException(msg, ex); 126 } 127 } 128 129 /** 130 * Some output streams synchronize writes while others do not. 131 * @param bytes The serialized Log event. 132 * @throws AppenderLoggingException if an error occurs. 133 */ 134 protected void write(final byte[] bytes) { 135 write(bytes, 0, bytes.length); 136 } 137 138 protected synchronized void close() { 139 final OutputStream stream = os; // access volatile field only once per method 140 if (stream == System.out || stream == System.err) { 141 return; 142 } 143 try { 144 stream.close(); 145 } catch (final IOException ex) { 146 LOGGER.error("Unable to close stream " + getName() + ". " + ex); 147 } 148 } 149 150 /** 151 * Flushes any buffers. 152 */ 153 public synchronized void flush() { 154 try { 155 os.flush(); 156 } catch (final IOException ex) { 157 final String msg = "Error flushing stream " + getName(); 158 throw new AppenderLoggingException(msg, ex); 159 } 160 } 161}